Correct Answer: B

Rationale: The correct answer is B: derived units. When base units (such as grams or milliliters) are combined, as seen in g/mL (grams per milliliter) for density, they form derived units. Derived units measure complex quantities that are derived from combinations of base units. Choice A, 'combined units,' is incorrect as it does not specifically refer to the formation of new units from base units. Choice C, 'base units,' is incorrect because base units are the fundamental units from which all other units are derived, not the combinations of units. Choice D, 'calculated units,' is incorrect as it does not accurately describe the concept of combining base units to form a new unit like g/mL for density.

Correct Answer: B

Rationale: The correct answer is B: 1000 grams. This is because by definition, 1 kilogram is equal to 1000 grams. Choice A, 100 grams, is incorrect as it underestimates the actual conversion. Choice C, 500 grams, and Choice D, 2000 grams, are also incorrect as they do not align with the correct conversion factor of 1 kilogram to 1000 grams.

Correct Answer: A

Rationale: To convert 0.004 to a ratio, we first express it as 4/1000, which simplifies to 1/250. Hence, 0.004 is equivalent to the simplified ratio of 1:250. Choice B, 4:35, is incorrect as it does not reflect the correct conversion. Choice C, 7:28, is incorrect because it does not represent the simplified ratio of 0.004. Choice D, 4:00, is incorrect as it does not simplify to the original decimal value.

Correct Answer: D

Rationale: The correct answer is D: 1,000 mg. This is because 1 gram is equivalent to 1,000 milligrams. To convert grams to milligrams, you multiply by 1,000. Choices A, B, and C are incorrect. Choice A (1 mg) is the smallest unit, and it would take 1,000 of these to make 1 gram. Choice B (10 mg) is also too small, as it would require 100 of these to equal 1 gram. Choice C (100 mg) is closer, but it still falls short of the correct conversion, which is 1,000 mg in 1 gram.

Correct Answer: C

Rationale: To convert liters to milliliters, you need to multiply by 1000 since there are 1000 milliliters in 1 liter. Therefore, 3.75 liters x 1000 = 3750 milliliters. This means that option C, 3750 ml, is the correct conversion. Choices A, B, and D are incorrect because they do not reflect the correct conversion from liters to milliliters.